High Flow Nasal Cannula (HFNC) Initiation Flow Rate Study

High Flow Nasal Cannula (HFNC) Initiation Flow Rate Study - A Single Center, Randomized Controlled, Feasibility Study

The investigators propose an open label, non-blinded, single center randomized controlled feasibility study to find the optimal initial HFNC flow rate in children less than 12 months old with clinically diagnosed moderate to severe bronchiolitis. This feasibility study is projected over December 2020 to April 2023. The study is consisted of 3 arms, comparing HFNC therapy at 1 L/kg/min, 1.5 L/kg/min, and 2 L/kg/min (20 L/min max). Moderate to severe bronchiolitis is defined clinician's assessment for the need for ICU level of care. The primary outcome is treatment response to HFNC therapy defined by RDAI/Respiratory Assessment Change Score (RACS) ≥ 4 at 4 hours of therapy. Secondary outcome measures comprise of treatment failure requiring an escalation of care during the first 24 hours of HFNC therapy, duration of HFNC and simple nasal cannula therapy, duration of simple nasal cannula therapy, hospital and PICU length of stay (LOS), time to treatment failure, and adverse events.

The infant that is randomized to the HFNC therapy arm 1 will be placed on high flow at 1 L/kg/min (up to a maximum of 20 L/min) on fraction of inspired oxygen (FiO2) of 21 %. They will remain on FiO2 of 21% for a minimum of 10 minutes while monitoring SpO2. If oxygen saturation (SpO2) is <90%, FiO2 will be slowly increased to maintain SpO2 ≥ 90 %.

The infant that is randomized to the HFNC therapy arm 2 will be placed on high flow at 1.5 L/kg/min (up to a maximum of 20 L/min) on fraction of inspired oxygen (FiO2) of 21 %. They will remain on FiO2 of 21% for a minimum of 10 minutes while monitoring SpO2. If SpO2 is <90%, FiO2 will be slowly increased to maintain SpO2 ≥ 90 %.

The infant that is randomized to the HFNC therapy arm 3 will be placed on high flow at 2 L/kg/min (up to a maximum of 20 L/min) on fraction of inspired oxygen (FiO2) of 21 %. They will remain on FiO2 of 21% for a minimum of 10 minutes while monitoring SpO2. If SpO2 is <90%, FiO2 will be slowly increased to maintain SpO2 ≥ 90 %.

Patients placed on High Flow Nasal Cannula by treating physician will be randomized to initial flow rates of 1 L/kg/min, 1.5 L/kg/min, or 2 L/kg/min

Determined by Respiratory Distress Assessment Instrument (RDAI) score and Respiratory Assessment Change Score (RACS) and heart rate improvement by 10%. The RDAI score assigns a score base on respiratory rate (RR), extent of wheezing, and retractions. It ranges from 0-17, higher score indicates severe bronchiolitis. To determine RACS: A decrease in RR by 10% is +1 change unit. Increase of 10% was defined as -1 change unit. Subsequent RDAI score is subtracted from the previous RDAI score to obtain the change. (ie. if initial score is 7 and the reassessment score is 3, the patient has a score of +4) Positive score is indicative of improvement, and negative score demonstrates deterioration. The overall RACS is calculated as the sum of change scores. Improvement is defined as RACS ≥ 4 positive units. No improvement was defined as RACS < 4 positive units.

Need for an increase in initial flow setting as determined by treating physician during the first 24 hours of hospitalization Escalation to other forms of non-invasive ventilatory support (i.e. NCPAP or BIPAP) Need for invasive ventilation

Inclusion Criteria: Patients less than 12 months of age Clinical signs of moderate to severe bronchiolitis defined by American Academy of Pediatrics Requires ICU level of care by clinicians' discretion Requiring HFNC support Exclusion Criteria: Infants who required immediate need for respiratory support such as non-invasive positive pressure ventilation (NIPPV) or invasive ventilation Congenital heart disease, Immunocompromised state Upper airway obstruction Chronic lung disease Bronchopulmonary dysplasia, Home oxygen therapy requirement Acute trauma patients Baseline craniofacial malformations Admitted to the neonatal or cardiac ICUs Patients who are admitted to the floor